In view of the problems of one-sided appraisal when using single character parameter to evaluate geomagnetic map suitability, multi-attribute decision making method based on maximum deviation and maximum entropy is applied to the overall evaluation of suitability. Geomagnetic map character parameters such as standard deviation, roughness, correlation coefficient and entropy are considered to achieve the synthetical evaluating indicator by setting the weight coefficient. By simulation using correlation matching algorithm, the results indicate the favourable consistency between synthetical evaluating indicator and matching probability. The bigger synthetical evaluating indicator is, the higher matching probability is. It is reasonable to treat synthetical evaluating indicator as quantitative basis of suitability.